Problem

When multiple Codex sessions are open at once, terminal tabs and windows are hard to distinguish from each other. The existing status line only helps once the TUI is already focused, so it does not solve the "which tab is this?" problem.

This PR adds a first-class /title command so the terminal window or tab title can carry a short, configurable summary of the current session.

Screenshot

Mental model

/statusline and /title are separate status surfaces with different constraints. The status line is an in-app footer that can be denser and more detailed. The terminal title is external terminal metadata, so it needs short, stable segments that still make multiple sessions easy to tell apart.

The /title configuration is an ordered list of compact items. By default it renders spinner,project, so active sessions show lightweight progress first while idle sessions still stay easy to disambiguate. Each configured item is omitted when its value is not currently available rather than forcing a placeholder.

Non-goals

This does not merge /title into /statusline, and it does not add an arbitrary free-form title string. The feature is intentionally limited to a small set of structured items so the title stays short and reviewable.

This also does not attempt to restore whatever title the terminal or shell had before Codex started. When Codex clears the title, it clears the title Codex last wrote.

Tradeoffs

A separate /title command adds some conceptual overlap with /statusline, but it keeps title-specific constraints explicit instead of forcing the status line model to cover two different surfaces.

Title refresh can happen frequently, so the implementation now shares parsing and git-branch orchestration between the status line and title paths, and caches the derived project-root name by cwd. That keeps the hot path cheap without introducing background polling.

Architecture

The TUI gets a new /title slash command and a dedicated picker UI for selecting and ordering terminal-title items. The chosen ids are persisted in tui.terminal_title, with spinner and project as the default when the config is unset. status remains available as a separate text item, so configurations like spinner,status render compact progress like ⠋ Working.

ChatWidget now refreshes both status surfaces through a shared refresh_status_surfaces() path. That shared path parses configured items once, warns on invalid ids once, synchronizes shared cached state such as git-branch lookup, then renders the footer status line and terminal title from the same snapshot.

Low-level OSC title writes live in codex-rs/tui/src/terminal_title.rs, which owns the terminal write path and last-mile sanitization before emitting OSC 0.

Security

Terminal-title text is treated as untrusted display content before Codex emits it. The write path strips control characters, removes invisible and bidi formatting characters that can make the title visually misleading, normalizes whitespace, and caps the emitted length.

References used while implementing this:

• xterm control sequences
• WezTerm escape sequences
• CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences
• CERT VU#999008 (Trojan Source)
• Trojan Source disclosure site
• Unicode Bidirectional Algorithm (UAX #9)
• Unicode Security Considerations (UTR #36)

Observability

Unknown configured title item ids are warned about once instead of repeatedly spamming the transcript. Live preview applies immediately while the /title picker is open, and cancel rolls the in-memory title selection back to the pre-picker value.

If terminal title writes fail, the TUI emits debug logs around set and clear attempts. The rendered status label intentionally collapses richer internal states into compact title text such as Starting..., Ready, Thinking..., Working..., Waiting..., and Undoing... when status is configured.

Tests

Ran:

• just fmt
• cargo test -p codex-tui

At the moment, the red Windows rust-ci failures are due to existing codex-core apply_patch_cli stack-overflow tests that also reproduce on main. The /title-specific codex-tui suite is green.